(a) Field of the Invention
The present invention relates to a method and an apparatus for requesting uplink persistent scheduling in a mobile communication system.
(b) Description of the Related Art
An existing mobile communication system, for example, a long term evolution (LTE) mobile communication system provides semi-persistent scheduling (SPS) for periodic uplink resource scheduling without increasing an overhead due to transmission of a control channel per packet transmission, for the purpose of a periodic real-time service such as Voice over Internet Protocol (VoIP) in an uplink. An uplink SPS configuration is performed by a radio resource control (RRC) reconfiguration process, and an SPS period is set in this process. An uplink SPS allocation request is performed by transmitting a buffer status report (BSR) sub-header through a scheduling request (SR) physical uplink control channel (PUCCH) or random access (RA) process, and a BSR includes a size of data that are waiting in a buffer of a terminal. SPS activation or allocation is performed by a physical downlink control channel (PDCCH), and SPS allocation information includes a SPS resource size, a modulation coding scheme (MCS), and the like.
However, in a real-time service sensitive to a delay among current and future mobile communication services, a period at which traffics are generated may be changed depending on a time, and a size of traffic data generated per period may also be changed. In an existing LTE SPS scheme, the RRC reconfiguration process should be again performed in order to change an SPS transmission period. In addition, for the purpose of low delay transmission, data should be allocated in a state in which a data packet arrival point in time and an SPS transmission point in time are as possible as close to each other. However, in the existing LTE SPS scheme, a means informing a base station of a time difference between the data packet arrival point in time and the SPS transmission point in time at the terminal is not present. In addition, an existing BSR, which indicates a size of entire data that are currently waiting in the buffer of the terminal, does not mean a size of data that are to be transmitted per SPS transmission period.
Therefore, a method for low delay and efficient semi-persistent scheduling (SPS) in an uplink has been demanded.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.